Photogating induced high sensitivity and speed from heterostructure of few-layer MoS2 and reduced graphene oxide-based photodetector

Over the past few years, two-dimensional transition metal dichalcogenides (2D-TMDC) have attracted huge attention due to their high mobility, high absorbance, and high performance in generating excitons (electron and hole pairs). Especially, 2D molybdenum disulfide (MoS2) has been extensively used in optoelectronic and photovoltaic applications. Due to the low photo-to-dark current ratio (I-photo/dark) and low speed, pristine MoS2-based devices are unsuitable for these applications. So, they need some improvements, i.e., by adding layers or decorating with materials of complementary majority charges. In this work, we decorated pristine MoS2 with reduced graphene oxide (rGO) and got improved dark current, I-photo/dark, and response time. When we compared the performance of pristine MoS2 based device and rGO decorated MoS2 based device, the rGO/MoS2-based device showed an improved performance of responsivity of 3.36 A W-1, along with an I-photo/dark of about 154. The heterojunction device exhibited a detectivity of 4.75 x 10(12) Jones, along with a very low response time of 0.184 ms. The stability is also outstanding having the same device performance even after six months.

Automated summary

In recent years, there has been significant interest in two-dimensional transition metal dichalcogenides (2D-TMDC) due to their exceptional properties in generating excitons. Among them, two-dimensional molybdenum disulfide (MoS2) has been widely used in optoelectronic and photovoltaic applications. However, the original MoS2-based devices are not suitable for these applications due to their low performance. This study demonstrates that by decorating pristine MoS2 with reduced graphene oxide (rGO), the performance of the devices can be greatly improved in terms of dark current, photo-to-dark current ratio, and response time.